My Vaio FE21B laptop has started to play up with low screen brightness on battery. I had the same problem just after I bought it and I recall a fix in the forum saying it was an Adobe Photoshop Elements related bug, I think to do with colour palettes. As far as I can remember I deleted an Adobe created file and the problem went away, but can't now remember the sequence of steps or where the Adobe file was created and what it was called. Screen works fine on mains power, but on battery is too dim and if you increase it with Fn F6 it only retains higher brightness for 10 seconds or so before reverting to dim once again. Any ideas much appreciated (I have already checked power management in Control Panel and it is set correctly). Thanks.
George